Bis[1,2-bis­(eth­oxy­carbon­yl)ethene-1,2-dithiol­ato-κ2 S,S′]bis­(η5-penta­methyl­cyclo­penta­dien­yl)tetra-μ3-sulfido-diiron(IV)diiron(III)(3 Fe—Fe)

Shohei Ito; Nozomu Hisamichi; Tsugiko Takase; Shinji Inomata

doi:10.1107/S1600536813005564

. 2013 Mar 2;69(Pt 4):m181. doi: 10.1107/S1600536813005564

Bis[1,2-bis(ethoxycarbonyl)ethene-1,2-dithiolato-κ² S,S′]bis(η⁵-pentamethylcyclopentadienyl)tetra-μ₃-sulfido-diiron(IV)diiron(III)(3 Fe—Fe)

Shohei Ito ^a, Nozomu Hisamichi ^a, Tsugiko Takase ^b, Shinji Inomata ^a,^*

PMCID: PMC3629468 PMID: 23633986

Abstract

The title compound, [Fe₄(C₁₀H₁₅)₂(C₈H₁₀O₄S₂)₂S₄], contains a twisted Fe₄S₄ cubane-like core. A twofold rotation axis passes through the Fe₄S₄ core, completing the coordination of the four Fe atoms with two pentamethylcyclopentadienyl ligands and two chelating dithiolate ligands. There are three short Fe—Fe and three long Fe⋯Fe contacts in the Fe₄S₄ core, suggesting bonding and non-bonding interactions, respectively. The Fe—S bonds in the Fe₄S₄ core range from 2.1523 (5) to 2.2667 (6) Å and are somewhat longer than the Fe—S bonds involving the dithiolate ligand.

Related literature

For details of the synthesis, see: Inomata et al. (1995 ▶). For related structures, see: Inomata et al. (1990 ▶, 1994 ▶). For general background to compounds with iron–sulfur cubane-type clusters, see: Holm (1977 ▶); Holm et al. (1990 ▶).

Experimental

Crystal data

[Fe₄(C₁₀H₁₅)₂(C₈H₁₀O₄S₂)₂S₄]
M _r = 1090.65
Monoclinic,
a = 23.4532 (5) Å
b = 10.4466 (2) Å
c = 18.3113 (3) Å
β = 90.6186 (7)°
V = 4486.14 (15) Å³
Z = 4
Mo Kα radiation
μ = 1.69 mm⁻¹
T = 296 K
0.30 × 0.20 × 0.20 mm

Data collection

Rigaku R-AXIS RAPID diffractometer
Absorption correction: multi-scan (REQAB; Jacobson, 1998 ▶) T _min = 0.560, T _max = 0.714
21429 measured reflections
5111 independent reflections
4694 reflections with I > 2σ(I)
R _int = 0.044

Refinement

R[F ² > 2σ(F ²)] = 0.030
wR(F ²) = 0.080
S = 1.06
5111 reflections
254 parameters
H-atom parameters constrained
Δρ_max = 0.50 e Å⁻³
Δρ_min = −0.33 e Å⁻³

Data collection: RAPID-AUTO (Rigaku, 2006 ▶); cell refinement: RAPID-AUTO; data reduction: RAPID-AUTO; program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ▶); software used to prepare material for publication: CrystalStructure (Rigaku, 2006 ▶).

Supplementary Material

Click here for additional data file.^{(28.8KB, cif)}

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536813005564/wm2725sup1.cif

e-69-0m181-sup1.cif^{(28.8KB, cif)}

Click here for additional data file.^{(250.4KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813005564/wm2725Isup2.hkl

e-69-0m181-Isup2.hkl^{(250.4KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected bond lengths (Å).

Fe1—Fe1ⁱ	3.3743 (3)
Fe1—Fe2	2.7253 (4)
Fe1—Fe2ⁱ	3.2683 (3)
Fe1—S1	2.1956 (5)
Fe1—S1ⁱ	2.2551 (5)
Fe1—S2	2.1749 (5)
Fe2—Fe2ⁱ	2.7619 (3)
Fe2—S1	2.2736 (5)
Fe2—S2	2.1523 (5)
Fe2—S2ⁱ	2.2667 (6)
Fe2—S3	2.1541 (5)
Fe2—S4	2.1934 (6)

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Symmetry code: (i) Inline graphic .

supplementary crystallographic information

Comment

Iron-sulfur cubane-type clusters have extensively been investigated as model systems of metal-containing proteins (Holm, 1977; Holm et al., 1990). Among these compounds, the Fe₄S₄ core is usually surrounded by the same supporting ligand (L) yielding a moiety Fe₄S₄L₄. However, mixed-ligand-type clusters are rather rare. Previously, we succeeded to prepare this type of iron-sulfur cluster from the reaction of (C₅Me₅)₂Fe₂(CO)₄ ((Cp*)₂Fe₂(CO)₄) with S₈ and diphenylacetylene (Inomata et al., 1990; 1994). One of the products was [Fe₄(Cp*)₂(Ph₂C₂S₂)₂(µ₃-S)₄], in which two Cp* ligands and two diphenyldithiolate ligands are additionally bonded to the Fe₄S₄ core. In order to expand our research on this subject, we prepared a cluster containg bis(ethoxycarbonyl)dithiolate ligands instead of diphenyldithiolate ligands. Here we report the structural details of the title compound [Fe₄(C₁₀H₁₅)₂(C₈H₁₀O₄S₂)₂S₄] or [Fe₄(Cp*)₂{(EtO₂C)₂C₂S₂)}₂(µ₃-S)₄], (I).

Compound (I) contains a twisted Fe₄S₄ cubane-like core surrounded by two Cp* ligands and two dithiolato ligands {(EtO₂C)₂C₂S₂} (Fig. 1). A crystallographic twofold rotation axis passes through the Fe₄S₄ core and completes the coordination environment of all iron atoms. There are three iron—iron bonds of 2.7253 (4) and 2.7619 (3) Å (Table 1). The remaining three Fe···Fe distances are very long (3.2683 (3) and 3.3743 (3) Å), indicating no bonding interactions (Table 1). The iron—sulfur distances in the Fe₄S₄ core range from 2.1523 (5) to 2.2667 (6) Å and are normal values (Table 1). On the other hand, the distances between iron and sulfur in the dithiolato ligand are somewhat short (2.1541 (5) and 2.1934 (6) Å) (Table 1).

Experimental

The title cluster compound was prepared according to the literature method (Inomata et al., 1995) by using diethyl acetylenedicarboxylate instead of dimethyl acetylenedicarboxylate.